Improved machine for dressing stone



UNTTED STATES PATENT OEETCE.

T. H. LEAVITT, OF BOSTON, MASSACHUSETTS.

IVNIPROVED MACHIN. FOR DRESSING STONE.

Specification forming part of Letters Patent N'O. 95,238, dated September 28, 1869.

specification, is a description ot my invention sufiicient to enable those skilled in the art to practice it.

Myinvention relates particularly to an organization of mechanism for grinding or dressing stone, the improvements being, however, applicable in whole or in part to machines for grinding, surfacing, or dressing other material.

The invention `consists primarily in combin` in g with a reciprocating table or carriage moving upon horizontal ways or rails a rotary grinder cylinder or disk, the grinding-surtace of which is made up of a series of segmental, sectoral, or annular blocks, made capable of adjustment or of displacement and replacement, `so that such changes may be readily made as are required by the nature of the material to be ground, the figure to be produced, or the wear of the tools. These grinding-surfaeesdo not in themselves reduce the material, but are the carriers or vehicles by which' abrasive powder, paste, or granulated abrasive matter is held to and ground against the stone or other material, which, by the action of the abrader (produced by the movement ot' the carriers) is brought to a plane or irregular form corresponding to the form ot' the acting surfaces of the carriers.

The invention also consists in certain details of mechanism chietly auxiliary to the employment of these sectional rotary grinders or laps.

The drawing represents a machine embodying my improvements.

A shows'the machine inside elevation. B

is an endview thereof.

a denotes the frame upon ways or rails, at

the top ot' which rests and slides the horizontal reciprocating carriage or table c, that sup' ports the material to be dressed, the longitudi` a cylinder, as seen at e, mounted upon a horizontal shaft, f, or a disk7 as seen at g, at the foot of a vertical shaft, 71 and, whether one or the other, it is composed oi a series ot' sectional pieces, the outer surfaces ot which form the carriers for presenting the abra-der. The cylinder-carrying shaft j' is journaled in bearings i, sliding in the uprights d, said bearings being supported n vertical screw-shafts k, turn- 'ing i'n bearings inthe posts d, the shafts being simultaneusly'rotated by a cross-shaft, Z, carrying"bevel-gears:ommeshing into and driving bevel-gears n on the upper ends of the two screw-shafts.v :By these means the cylinder is lowered as 'the surface ot' lthe stone is ground away by it. The` disk is yraised and lowered by'analogous means, its shaft being journaled in bearings at the center of cross-beams, the

opposite ends of' one or both ot' which carry nuts or boxes worked by vertical screw-shafts, having gears driven by gears upon a crossshaft. i

The cylinder e is-driven by suitable gearing connecting its shaft to the main shaft o, and the cylinder is constructed as follows: Between two heads, p, located on the shaft, l place a pulley, r, made whole or of a series o1 narrow pulleysor collars, and over this cylinder I slip a series of grinder-rings, each made up ot' segmental blocks s, each ot' which has a series of holes through which pass long bolts t, extending from head to head, the adjacem segments being clamped tightly together by means ot' 4these bolts. Each segment-forme( ring corresponds in inner diameter to the di ameter ofthe 4cylinder e, and their outer diam eters are the same, so that when bolted to gether they form a grinding-cylinder of uni form diameter throughout, so far as relates t1 the respective sections composing the cylinder One end of the outer curved surface of each seg ment may retreat from the cylindrical grinder surface, as seen at u, forming between the ad jacent ends of each two adjacent segments slight recess, which will takeup the abrasiv powder as the cylinder rotates. 'The grinder-blocks may be made of an suitable material adapted to presenting an rubbing'the" abrader against the surface to b reduced', wood,"metal, leather, or other man rial being employed, according to the natur ofthe material to be worked or the surfacet be produced. The belt-holes in the blocl may be slotted to permit slight adjustments of the grinder-suriaces.

Then a series of collars are used to form the segment-carrying cylinder they are preferably made oi' widths varyingfrom the widths of the segments, so as to break joints between the segments and collars. The cylinder being thus constructed, and a block or slab of stone to be reduced bein placed and fastened upon the carriage, and the cylinder being fed down to thc plane ot' the surface of the stone, the cylinder and bed are set in motion, and sand, emery, or other abrasive material and water being then i'ed to the surface of the cylinder, the surface of the stone will be rapidly and uniformly' reduced to a practically' perfect plane.

For conduct' the abrasive agent and the water to the cylinder a mechanism may be used as follows: The abrader is placed in a hopper or reservoir, r, at Jthe bottom of which may be a screen for keeping back the coarse grains or particles. 'lhis hopper discharges at bottom into the top ot' a chute or conductor, 1e, which extends down at the front of the cylinder, the bottom of the chute being formed into a long narrow discharge-slit extending the length of the cylinder, and discharging the powder entirely across the same. rlo guide the powder to a portion of the length ot' the slit I use guides m, hung on pins y, by means otl which euch may be swung toward or from the adjacent Lr of the chute, and just under the bottom ofthe hopper or at the top of the chute I place valves e', by turning which the amountI of powder delivered into the chute may be regulated as circumstances may render desi `able. lletween the hopper and the cyliuder is a trough, c2, extending the length of the cylinder and pierced at bottom with holes b". lnlo this trough water or other liquid is let from any convenient source of supply, and through the holes the water pcrcolates and drops upon inc cylinder, mingling with and moistcning the sand supplied from the hopper. 'lhe water may he let directly into t c hopper and run through with the sand; but the arrangement shown l'. consider preferable.

'lhc disk grinder (the ilat surface of which is presented to the stone in grinding) is constructed as follows:

g denotes a circular head or disk iixed upon the foot of the. vertical shaft h. rI he bottom of the head provided with a Series of sectoral grindcrblceks, c2, the two radial edges et' each of which may have tongues d3, .litting under lips ci" on radial strips f2, fixed to the under side ot' the head. When in position the circular edge ot cach sector projects out beyond the periphery ot' the head` except at the upper corner, where the edge retreats to aline corresponding with the periphery ot' the head, and a hoop or band, g2, slipped over the pe riphery, drops down around the Sectors and rests ou top oi' their projecting edges, thereby confining the| Mors in position. At the celiter of the head is a receiver, h2, into the top of which the sand or other abrading material is conducted from a hopper, t2. This receiver discharges the abrader into a series ct' conductors or passagesJz, leading through the disk and into a common axial passage, 7a2, as seen at G, from which passage the sectors radiate, as seen at D, the sand or abrading powder and water running through the hopper and conductors down upon the stone and heilig thrown laterally between the adjacent sectors by centrifugal force and taken up by the sev eral sectors, one edge of each of which may he inclined, as seen at D, the better to take the sand.

The hopper may be provided with a screen to keep back the too-coarse particles ot' the abrasive agent.

rlhe disk may be also provided with a series ot' holes, Z2, running through it and disposed radially, as seen atl), sand and water passing through these holes from the top of the disk, being delivered between the sectors, each series of holes heilig between two sectors; and to prevent the sand from being thrown from the'top ot' the disk by centrifugal force, the disk may have an upturned peripheral flange, m2. as seen at C.

The cylinder grinder and the disk grinder may bc used together in grinding pla-ne faces of stone or other material during the reciprocatory movements ot' the carriage, or either may be used alone; but, besides their adaptation to produce such plane surfaces, each may be used in producing moldings, iluted or beaded work, the cylinder to produce straight work of this kind, and the disk circular or sections of circular work. 'For this purpose cach segmental grinder-block on the cylinder will have a peripheral grinding-edge the converse of the surface to be produced upon the stone or other material as it is fed under the cylinder, as seen, for instance, at E, F, and G; and for circular work the face of each grinder-sector will have a form in radial section corresponding in form to a corresponding section ot' the circular work to be produced, as will be readily understood, the stone being of course held stillwhile the rotating disk-sectors are operating, a section ot' one of such sectors being shown at I.

Along pillar, cylinder, or column may be tinted, grooved, or polygonally faced by the cylinder grinder by mounting it between suitable heads at opposite ends ofthe carriage on center points, (logging the work in stationary position relatively to the carriage, the car riagc being then reciprocated asin grinding plane and wide surfaces. After each groove, bead, or polygonal face is formed the column is turned upon its centers: to bring it into position for the formation, in the same manner, of the next groove, flute, bead, or face.

For producing the curved surfaces of building stone for swell fronts 7 I use an auxiliary table or carriage, similar to that shown at H, upon the under surface ot' which arc curved cross-pieces al, which rest and slide upon curved transverse rails o2. The under surface of the bed has fixed upon it circular gearracks p2, which engage with the teeth of pinions g2 on asnaft,r2. This carriage is mounted upon the table or carriage c, the blocksbeing laid crosswise of the auxiliary table, (the sur` faces to be reduced uppermost,) and the surfaces over the center ot'- the table being reduced (under the rotary movements of the grinders and the longitudinal movementsof the carriage) down to a surface tangential ,to the curve to be formed. The shaft r2 is gradually rotated in each direct-ion, causing the table to slide on the curved rails and reducing the surfaces of all the blocks to a corresponding or concentric curve.

At the opposite sides of the table or carriage c, I place troughs s2, the tops of which (adjacent to the bed) are on a plane with the surface of the bcd,lso that all water and semi- `iuid matter (made up of water, the material ground off from the stone, and the abrader) escaping from the bed, will pass off of the carriage into the troughs,from whence this WateryI and semi-duid matter may be drawn oft by suitable conduits, this provision not only keeping the frame-work and mechanism of the machine dry and in good conditiombut also keeping all the space about the machine clean and neat.

Each sand-containing hopper is placed upon a suitable stand or frame, t2, over the grinder, and to preserve the relative distance between the grinder and hopper, this frame may be supported upon boxes or nuts a2, the screw-threads v of which rest agai nst the adjacent screw-shafts,

so that the same'vertical movements imparted to the grinder and also im parted to the hopper.

By means of a grinding mechanism organized to operate as shown and described Work may be very cheaply performed, the sectional grinders or laps may be readily renewed as they become Worn, one kindof grinder may be easily substituted for another, a very great Variety ot'` work can be accomplished in the same machine With interchangeable devices, and the machine is enduring, and is simple in construe' tion and operation.

When the cylinder and the disk grinder operate at the same time in reducing or surfacing a stone to a flat surface it will be obvious that any tendency of the cylinder to make grooves upon the stone or to grind the surface irregularly is corrected by the disk grinder, which Works laterally over the surface of the stone, While each portion or segment of the cylinder works longitudinally with respect thereto.

I claiml. In a machine for dressing stone, having a reciprocating work-supporting table or carriage, a horizontally-axled grinding-cylinder, the grinding-surface'of which is composed of a series of peripheral segments bolted together and confined between the cylinder-heads, substantially as described.

2. A horizontal disk grinder composed of sectoral blocks fastened to the lower face of a rotary head fixed to the foot of avertical shaft, the sectors beingso confined in position that any one or more may be removed for repairs or replacement.

3. In a grinding-machine having a reciprocating Work-supporting table or carriage, the combination of a cylinder grinder rotating on a horizontal axis, with a disk grinder at the foot of a rotary vertical shaft, substantially as shown and described. v

4. In a stone-dressing machine, a reciprocating carriage having long side troughs for receiving the liquid and semi-liquid matter escaping from the stone, the troughs being fixed to or forming part of the table.

5. In combination with the sand-receiving hopper, a chute or conductor so constructed and arranged as to convey the sand to the wholelength of the grinding-cylinder, and having provision for controlling and regulating the feed of the sand.

6. In combination with a reciprocatingworksupporting table or bed, mounting the bed upon curved rails or Ways for lateral curvilinear movement, substantially as and for the purpose described.

T. H. LEAVITT.

Wi tn esses J. B. CROSBY, FRANCIS GoULD. 

